Question

An element X (atomic number $$17$$ ) reacts with an element Y (atomic number$$20$$) to form a divalent halide.
The element x is:
A. a Metal
B. a Non Metal
C. a Metalloid
D. None of these

Answer 1

Hint: A metal is an element that creates positive ions (cations) readily and it has a metallic bond and Non-metals are the elements which form negative ions by accepting or gaining electrons. Non-metals usually have $$4,5,6$$ or $$7$$ or electrons in their outermost shell.

Complete Step by step answer: The electronic configuration of element 'X' with atomic number $$17$$ is $$2,8,7,$$ it has $$7$$ valence electrons. Ground state electronic configuration is$$1s^{2}2s^{2}2p^{6}3s^{2}3p^5$$. Therefore, it lies in the group$$17\left(10+7\right)$$ . Since in element X, the third shell is being filled, it lies in the third period. X is chlorine.
 It is a Non metal.

The electronic configuration of element 'Y' with atomic number $$20$$ is $$2,8,8,2.$$The ground state electron configuration is 20Ca:$$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^2$$, it has $$2$$ valence electrons, It lies in group $$2$$ and element Y, fourth shell is being filled, It lies in $$4th$$ period, Y is calcium.
Since, element X is (Chlorine) has seven electrons in the valence shell and needs one more electron to complete its octet. Therefore it is non-metal. Element Y has two electrons in the valence shell which it can easily lose to achieve the stable electronic configuration of the nearest inert gas, therefore, it is a metal.
Element X and element Y react to form a divalent halide, i.e $CaC{l}_2$ in divalent halide.

Hence the correct option is B.

Note: Nonmetals have high electronegative. This means that the atoms of nonmetals have a strong tendency to attract more electrons and A metalloid is an element that has properties that are intermediate between metals and nonmetals.